patch 9.0.1559: function argument types not always checked

Problem:    Function argument types not always checked and using v:none may
            cause an error.
Solution:   Check argument types once the function type is known.  Do not give
            an error for using v:none as an argument. (closes #12200)
diff --git a/src/version.c b/src/version.c
index 689b1a2..47079f5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1559,
+/**/
     1558,
 /**/
     1557,